Who makes Kirkland Signature Naproxen Sodium 220 mg, 400 Caplets?
As of September 28, 2026, the manufacturer of Kirkland Signature Naproxen Sodium 220 mg, 400 Caplets is Perrigo, per plant / registration code evidence.
The common claim
What’s commonly claimed, and what the evidence supports
Aleve-versus-Kirkland comparisons, and most "who makes Kirkland naproxen" answers, name Perrigo, and both FDA records and Costco's own listing back that for this product. Kirkland Signature Naproxen Sodium 220 mg (NDC 63981-368) is marketed under ANDA 074661, which Drugs@FDA lists to sponsor Perrigo, the largest US private-label OTC drugmaker, and Costco's own product listing for the 400-count bottle independently carries "L Perrigo Company" in its manufacturer field. The two routes agree: Kirkland Signature naproxen sodium is manufactured by Perrigo, per Costco's product-catalog manufacturer field (L. Perrigo Company) corroborated by FDA's Drugs@FDA record for ANDA 074661. FDA's application holder is the responsible party, not necessarily the plant that presses each caplet, which is why the retailer's own field naming the same company is what closes the attribution. Unlike Kirkland ibuprofen, which Costco splits across several contract makers, the naproxen line shows a single FDA application, so there is one evidenced answer across the line.
Evidence & sources
Each source is graded on the six-tier evidence rubric, where tier 1 is strongest. Sources are archived, so a citation still works if the original page moves or goes behind a paywall.
Tier 3
DailyMed's FDA-sourced label "KIRKLAND SIGNATURE NAPROXEN SODIUM" (naproxen sodium 220 mg tablet, film coated) names Costco Wholesale Company as the labeler (DUNS 103391843), lists NDC 63981-368 (marketed since 2007-06-04), and gives Marketing Category "Abbreviated New Drug Application" with Application Number ANDA074661. No establishment other than Costco appears on the SPL; the maker is reached only through the ANDA number.
Tier 3
Drugs@FDA resolves ANDA074661 (the application behind Kirkland Signature Naproxen Sodium 220 mg, NDC 63981-368) to sponsor PERRIGO, product NAPROXEN SODIUM 220MG, Over-the-counter tablet. On its own this join would cap the grade at probable: openFDA's manufacturer_name field only echoes the labeler (Costco Wholesale Company), so the maker is reached by joining the NDC to its ANDA sponsor, and the ANDA applicant is FDA's responsible party rather than necessarily the physical packer. Costco's own catalog manufacturer field naming L. Perrigo Company for the same item (see the Costco Business Delivery source) is the independent corroboration that carries the record to confirmed. Unlike Kirkland ibuprofen (multi-sourced across several ANDAs), the Kirkland naproxen line shows a single NDC under a single ANDA in the FDA NDC directory, so Perrigo covers the line as far as those records reach.
Tier 4
Costco's Business Delivery storefront (costcobusinessdelivery.com) serves the same US catalog data as costco.com and, unlike costco.com, can be fetched and archived. Its page for this item ('Kirkland Signature Naproxen Sodium, 400 ct', item 11833733) embeds catalog JSON whose manufacturer field reads mfName: "L PERRIGO COMPANY", L. Perrigo Company being Perrigo's principal US operating company (Allegan, MI). Read on August 30, 2026 and verified present in the Wayback snapshot created the same day. The costco.com consumer page for the same product (item 100220625) was also read live in a browser that day and carries the identical manufacturer-field value; costco.com cannot be archived, so the Business Delivery page is the citable copy. An internal catalog field rather than an editorial statement, and such fields can name a supplier-of-record rather than the plant; here it independently corroborates the FDA route (NDC 63981-368 -> ANDA 074661 -> sponsor Perrigo): the retailer and the regulator name the same company, which meets the rule for confirmed (Costco's manufacturer field plus an independent naming). The ANDA holder remains FDA's responsible party rather than a guaranteed physical packer; the retailer's own field agreeing with it is what closes the attribution.
Frequently asked
Who makes Kirkland Signature naproxen sodium?
Is Kirkland naproxen the same as Aleve?
Is Kirkland naproxen made by Perrigo?
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